1. Field of the Invention
The present invention relates to sensor systems and, more specifically, to a sensor system that senses the thickness of layers of liquids of different phases.
2. Description of the Prior Art
It is important to measure multiphase fluid levels in a variety of settings such as containers, drums, tanks, wells, rivers, oceans, and other surface and subsurface environments. Multiphase fluids are composed of liquids of different specific gravities such as light non-aqueous phase liquid (LNAPL), water, dense non-aqueous phase liquid (DNAPL), and emulsions. LNAPL is characterized by having a specific gravity less than that of water and DNAPL is characterized by having a specific gravity greater than that of water.
Current systems for measuring multiphase fluid levels include systems that use pressure transducers, optical sensors, float switches, ultrasonic sensors, magneto-restrictive, magneto-elastic, radar (pulse burst, guided-wave, frequency modulated continuous wave, and other radar-based technologies), radio frequency (RF), and related devices which are capable of measuring the level of a single phase liquid.
None of these devices are capable of measuring levels of several multiphase liquids simultaneously. Although two or more devices can be applied to measure the levels of multiphase liquids separately, none of the devices are capable of automatically computing and reporting the thicknesses of multiphase liquids or the elevations of multiphase liquids, simultaneously.
The space available to install multiple devices to measure multiphase liquids may be restricted by the narrow spaces of the container being measured. For example, a tank may not have a sufficient number of ports to accommodate more than one device, or a single available port might not be large enough to accommodate multiple devices. In measuring multiphase liquid levels in a well, the space within the well is generally too restricted to accommodate several different devices at the same time. Furthermore, it may not be possible to deploy other down-hole devices such as pumping systems or other recovery apparatus in small diameter wells.
Therefore, there is a need for a system that can sense the levels of different liquid phases simultaneously.